check out ian black's work

[jaxxzer]

https://github.com/IanTBlack/br_sensors

1. Used TEOS-10 pressure to depth conversion to compute depth.
2. Changed variable/function names to more closely match MS5837-30BA manual.
3. Combined read and temperature/pressure/depth/altitude functions into one.
4. temperature/pressure/depth/altitude are called independently of one another. They do rely on one another, but I formatted in a way that doesn't require users to call pressure before calling depth.
5. absolute_pressure() give the absolute pressure reading in user selected units
6. pressure() removes atmospheric pressure if given. if not it uses standard atmospheric pressure.